Because the rear hitch or bumper of a vehicle is not normally visible to a driver, hitching trailers to tow vehicles and other docking operations have long been considered a two-person operation. For example, a first person drives the tow vehicle in reverse towards a docking position while a second person provides feedback to the first driver, conveying to the driver feedback in the form of speed and direction to reach the docking position or docking vector information, the docking vector being the direction and distance of the target destination with respect to current location and orientation of the tow vehicle. For example, a helper assisting in hitching a trailer might yell to the driver, xe2x80x9cslight left, go slowxe2x80x9d or xe2x80x9cthe trailer hitch is twelve inches (30 cm) back and a few to the rightxe2x80x9d.
Most often, the tow vehicle/trailer hitch connection comprises a spherical joint formed by a steel ball attached at its lower end to a hitch bar extending from the tow vehicle, and a socket, open towards the bottom, that is attached to the trailer. The socket receives and captures the ball, allowing limited relative angular displacement in three degrees of freedom, thereby forming the spherical joint. In order for the disparate parts to mate, they must be properly aligned so that the socket may be lowered over the ball. This is particularly difficult when the trailer is too large or heavy to be handled by an individual. The vehicle must be precisely positioned to mate with the trailer by maneuvering the vehicle to align the ball with the socket. Of course, other types of hitches are known, as well as certain other docking requirements for vehicles. Each of these scenarios requires accurately controlling the vehicle to a docking position while the vehicle is in reverse and the target destination is not visible to the driver. The problem of docking the vehicle to a precise location, therefore, extends beyond trailering, although that may be the most common application.
Prior art attempts at resolving the problem described above have centered on providing visible or audible feedback to the driver during the docking maneuver, thereby allowing the docking operation without the second person providing feedback to the driver. Such systems use various sensors, including, for example, infrared light emitter/detectors, ultrasonic emitter/detectors, and other means for determining alignment of the ball and socket connectors. These devices however, do not provide precise information and still rely on the driver to accurately steer the vehicle to a precise location. Thus, the prior art hitching aids have not been very successful.
Disclosed is a system for assisting a driver of a vehicle in precisely reaching a target destination while the vehicle is in reverse. The system comprises a control unit, a hitch/docking (HD) sensor, a rear wheel steering actuator, and a control positioned for operation by the driver. The HD sensor is in communication with the control unit and measures the relative position of a target location with respect to a location on the vehicle. The rear wheel steering actuator is in communication with the control unit and steers at least a rear wheel of the vehicle. The driver operated control is also in communication with the control unit. The control unit, upon receiving a signal from the control, enters an HD mode in which the control unit operates the rear wheel steering actuator to maneuver the vehicle to bring the target location and the location on the vehicle into alignment.
The above described and other features are exemplified by the following figures and detailed description.